Selumetinib: First Approval.

Selumetinib (KOSELUGOTM; AZD6244, ARRY-142886) is a mitogen-activated protein kinase 1 and 2 (MEK1/2) inhibitor being developed by AstraZeneca for the treatment of tumours associated with neurofibromatosis and various cancers. Selumetinib has been granted orphan drug status as adjuvant treatment for thyroid cancer (in the USA) and as treatment for neurofibromatosis type 1 (in the USA and the EU) and, based on the results of the phase II SPRINT trial, was recently approved in the USA in paediatric patients with neurofibromatosis type 1 and symptomatic, inoperable plexiform neurofibromas. This article summarizes the milestones in the development of selumetinib leading to this first approval for the treatment of paediatric patients aged ≥ 2 years with neurofibromatosis type 1 who have symptomatic, inoperable plexiform neurofibromas.